The Effects of Physical Activity Timing and Adherence to Physical Activity Guidelines on Sleep in Children With <scp>ADHD</scp>

Regular physical activity (PA) has been shown to benefit sleep. However, the effects of PA timing and adherence to the WHO's recommended 60-min moderate-to-vigorous physical activity (MVPA) guideline on sleep are unclear, especially for children with ADHD who often experience sleep problems. This study examined whether timing of MVPA influenced objectively measured sleep, including sleep latency (SL), sleep efficiency (SE), total sleep time (TST), and wake after sleep onset (WASO), among children with ADHD. This cross-sectional study involved 253 children with ADHD (Mage = 8.60 ± 1.31 years, 81% boys). MVPA timing was categorized as more than 8 h before bedtime, 3-8 h before bedtime, and less than 3 h before bedtime. Meeting the MVPA guideline was defined as engaging in at least 60 min of MVPA daily. PA and sleep were recorded using an ActiGraph GT9X accelerometer for 7 consecutive days. Among the participants, 174 children (68.8%) met the WHO daily guidelines of 60 min of MVPA. These children had better sleep outcomes than those who did not meet the guideline, with shorter sleep latency, higher sleep efficiency, and less WASO. Regarding PA timing, meeting the MVPA guideline and MVPA time more than 8 h before bedtime were associated with reduced SL, improved SE, and reduced WASO. Conversely, MVPA time less than 3 h before bedtime was associated with decreased SE and increased WASO. Performing MVPA more than 8 h before bedtime and MVPA guideline attainment are crucial for improving sleep outcomes in children with ADHD.